纳米颗粒对sn58bi2fcu微焊点的改性与机理分析-(6090)

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1、哈尔滨理工大学工学硕士学位论文50nmCu颗粒的复合焊膏焊后剪切力降低程度较其它两种粒径的铜颗粒明显。关键词SnBi钎料；复合焊膏；纳米颗粒；微观组织；剪切性能-II-万方数据哈尔滨理工大学工学硕士学位论文StudyofModificationandMechanismofNano-ParticlesonSn58Bi/CuMicroSolderJointsAbstractInthedevelopmentprocessoflead-freesoldersinelectronicproducts,SnBisolderswaswidelyusedinthelow-temperaturep

2、ackaging,duetoitslowcost,lowmeltingpoint,lowthermalexpansioncoefficientandbettermechanicalproperties.However,SnBisoldersstillexistsomedisadvantagessuchaslowstrengthandhighbrittlenessetc.InordertooptimizethemicrostructureandpropertiesofSnBisolders,themechanicalmixingmethodwasusedtogetnanocompo

3、sitesolderpaste.Thispaperinvestigatedthemeltingcharacteristics,wettability,defectformationmechanism,microstructureandshearstrengthpropertiesofthecompositesolderpaste.Theresultsindicatedthattheadditionof3wt%ofnano-particlesintotheSn58Bisolderpasteresultedintheliquidustemperatureofnano-copperco

4、mpositesolderpasteandnano-nickelcompositesolderpasteincreasedby1.21and0.38℃comparedtotheSnBipaste,respectively.Themeltingrangeincreasedby1.16and0.33℃，respectively.Thespreadingcoefficientofcompositesolderpasteonthecoppersubstratewasdecreasedwiththeadditionofnano-particles.Thereasonwasthatthefl

5、uidityofthecompositesolderpastewasdecreasedintheprocessofmeltingduetoformationofhighmeltingtemperatureintermetalliccompounds.TheX-raythree-dimensionalandtwo-dimensionalimagingtechnologywasusedfordefectresearchafterreflow.Theresultsshowedthattheporosityincreasedwiththeincreaseofweightpercentof

6、nano-particles.Theporosityoccupiedhalfoftheareaofthesolderjointswhentheweightpercentofthecopperparticlesupto15%.Thecopperparticlesreactedwithtininthematrixintheprocessofmeltingandformedtheintermetalliccompounds.ThemeltingtemperatureoftheintermetalliccompoundswashigherthantheSnBimatrix.Thesold

7、erjointswithhighweightpercentcopperparticlesformedmoreintermetallic-III-万方数据哈尔滨理工大学工学硕士学位论文compounds,whichhinderedthespillofthegasproducedbytheflux.Asaresult,theporosityincreased.However,thecopperparticlesusedinthisstudybehavednoobvioussizeef